Merge pull request #28 from CruGlobal/add-user-endpoint

Add profile endpoint
Removing not null constraint from `cru_crs_auth_provider_identities.auth_provider_username` as there are in fact times when it should be null.
Fixing ConferenceService test
 - updating test to align with changes that have been made to the mock data.
Fixing broken PageServiceTest
Fixing broken BlockServiceTest
Fixing broken RegistrationServiceTest
Fixing broken AnswersServiceTest
Merge branch 'restore-service-tests' of http://github.com/CruGlobal/conf-registration-api into restore-service-tests